1. Technical Field
The present disclosure relates generally to a surgical stapling apparatus and, more specifically, to a surgical stapling apparatus having a single trigger for approximating anvil and cartridge assemblies and for ejecting an array of staples from the cartridge assembly.
2. Background of Related Art
Surgical stapling instruments used for applying parallel rows of staples through compressed living tissue are well known in the art, and are commonly used, for example, for closure of tissue or organs prior to transection, prior to resection, or in anastomoses, and for occlusion of organs in thoracic and abdominal procedures.
Typically, such surgical stapling instruments include an anvil assembly, a cartridge assembly for supporting an array of surgical staples, an approximation mechanism for approximating the anvil and cartridge assemblies, an alignment pin assembly for capturing tissue between the cartridge and anvil assemblies and for maintaining alignment between the cartridge and anvil assemblies during approximation and firing, and a firing mechanism for ejecting the surgical staples from the cartridge assembly. The approximation mechanism and the firing mechanism generally include distinct actuators for effecting approximation and firing of the staples. The alignment pin assembly can be manually operated to advance an alignment pin from the cartridge assembly into engagement with the anvil or, alternatively, the alignment pin assembly can be automatically actuated upon operation of the approximation mechanism. In instruments having a manually operated alignment pin assembly, the actuator for the alignment pin assembly is disposed at a location spaced from the handle of the instrument.
U.S. Pat. No. 4,930,503 to Pruitt discloses such a surgical stapling instrument. Pruitt""s instrument includes a manually operated alignment pin assembly, an approximation mechanism including a rotatable knob actuator and a firing mechanism including a pivotable trigger. In use, a surgeon must first approximate the anvil and cartridge members by rotating the knob actuator. Next, the surgeon can advance the alignment pin assembly by advancing a knob supported on the central body portion of the instrument. Thereafter, the instrument can be fired by pivoting the trigger towards a stationary handle of the instrument.
U.S. Pat. No. 5,697,543 to Burdorff also discloses a surgical stapling instrument having an approximation mechanism, a firing mechanism and an alignment pin mechanism. The approximation and firing mechanisms each include a distinct pivotable trigger actuator. The alignment pin mechanism is operatively associated with the approximation mechanism such that upon actuation of the approximation mechanism, the alignment pin assembly is automatically advanced.
Known prior art surgical staplers are lacking in several respects. Firstly, the use of multiple actuators to effect approximation and firing of the instruments complicate the manufacture and operation of the instrument and, in most cases, require the surgeon to use two hands to hold and operate the instrument. Secondly, the instruments in which the alignment pin assembly is operatively associated with the approximation mechanism require that the instrument be approximated to advance the alignment pin assembly, despite the fact that a surgeon may prefer to advance the alignment pin assembly prior to approximation. In contrast, the instruments in which the alignment pin assembly is manually advanced typically require the surgeon to use a second hand to actuate the alignment pin assembly.
Accordingly, a continuing need exists for a surgical stapling instrument which can be operated by a surgeon with a single hand and which includes an alignment pin assembly which can be automatically or manually advanced.
In accordance with the present disclosure, a surgical stapling device is provided which includes a frame having a proximal end and a distal end. A body defining a stationary handle is secured to the proximal end of the frame. A head portion including an anvil assembly and a cartridge assembly are supported on the distal end of the frame. The anvil and cartridge assemblies are movable in relation to each other between spaced and approximated positions. An approximation mechanism includes a clamp slide assembly having a distal end configured to support the cartridge assembly and a proximal end. A firing mechanism includes a thrust bar having a distal end positioned to be slidably received within the cartridge assembly. A pivotable trigger is supported on the body and is operably associated with the approximation mechanism and the firing mechanism such that the trigger is pivotable through an approximation stroke to approximate the anvil and cartridge assemblies and, subsequently, pivotable through a firing stroke to eject an array of staples from the cartridge assembly.
The presently disclosed surgical stapling device also has an alignment pin assembly which includes an alignment pin, a pin pusher and a bell crank. The alignment pin pusher is slidably supported on the frame between advanced and retracted positions. The alignment pin pusher includes a distal abutment member for engaging and advancing the alignment pin from a retracted position located within the cartridge assembly to an advanced position engaging the anvil assembly. The bell crank is operably connected to the clamp slide assembly and is releasably coupled to the pin pusher. Upon advancement of the clamp slide assembly, the bell crank is pivoted to concurrently advance the alignment pin pusher. The alignment pin pusher includes a pair of posts which extend through slots in the body. A thumb button is supported on each post. The thumb button(s) can be pushed prior to approximation of the device to manually advance the alignment pin assembly into engagement with the anvil assembly. The thumb buttons are positioned on the body such that a surgeon is able to manually advance the alignment pin assembly using the same hand that actuates the pivotable trigger.
A pawl mechanism is supported in the body and includes a clamping pawl and a firing pawl. The clamping pawl functions to prevent return of the approximation mechanism after the trigger has moved through approximately three quarters of the approximation stroke. The clamping pawl also provides an audible and tactile indication that the device has been moved to the approximately three quarter approximated position. The firing pawl functions to provide an audible indication that the device is in a fire-ready position. The firing pawl also functions to lock the trigger in a compressed position after firing of the device has occurred to provide a visual indication that firing has occurred. A release button is provided to return the approximation mechanism to the retracted position at any point of operation of the device. The pivotable trigger, the release button and the thumb button are all disposed adjacent the handle portion of the device and are operable by the surgeon using a single hand.
The anvil assembly of the surgical stapling device is provided with a stiffener plate to provide increased strength to the assembly. By using the stiffener plate, the head portion profile can be reduced in size.